Microbial amyloids induce interleukin 17A (IL-17A) and IL-22 responses via Toll-like receptor 2 activation in the intestinal mucosa.
Infect Immun
; 80(12): 4398-408, 2012 Dec.
Article
in En
| MEDLINE
| ID: mdl-23027540
ABSTRACT
The Toll-like receptor 2 (TLR2)/TLR1 receptor complex responds to amyloid fibrils, a common component of biofilm material produced by members of the phyla Firmicutes, Bacteroidetes, and Proteobacteria. To determine whether this TLR2/TLR1 ligand stimulates inflammatory responses when bacteria enter intestinal tissue, we investigated whether expression of curli amyloid fibrils by the invasive enteric pathogen Salmonella enterica serotype Typhimurium contributes to T helper 1 and T helper 17 responses by measuring cytokine production in the mouse colitis model. A csgBA mutant, deficient in curli production, elicited decreased expression of interleukin 17A (IL-17A) and IL-22 in the cecal mucosa compared to the S. Typhimurium wild type. In TLR2-deficient mice, IL-17A and IL-22 expression was blunted during S. Typhimurium infection, suggesting that activation of the TLR2 signaling pathway contributes to the expression of these cytokines. T cells incubated with supernatants from bone marrow-derived dendritic cells (BMDCs) treated with curli fibrils released IL-17A in a TLR2-dependent manner in vitro. Lower levels of IL-6 and IL-23 production were detected in the supernatants of the TLR2-deficient BMDCs treated with curli fibrils. Consistent with this, three distinct T-cell populations-CD4(+) T helper cells, cytotoxic CD8(+) T cells, and γδ T cells-produced IL-17A in response to curli fibrils in the intestinal mucosa during S. Typhimurium infection. Notably, decreased IL-6 expression by the dendritic cells and decreased IL-23 expression by the dendritic cells and macrophages were observed in the cecal mucosa of mice infected with the curli mutant. We conclude that TLR2 recognition of bacterial amyloid fibrils in the intestinal mucosa represents a novel mechanism of immunoregulation, which contributes to the generation of inflammatory responses, including production of IL-17A and IL-22, in response to bacterial entry into the intestinal mucosa.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Salmonella typhimurium
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Interleukins
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Interleukin-17
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Toll-Like Receptor 2
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Amyloid
Limits:
Animals
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Female
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Humans
Language:
En
Journal:
Infect Immun
Year:
2012
Document type:
Article
Affiliation country:
United States
Publication country:
EEUU
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ESTADOS UNIDOS
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ESTADOS UNIDOS DA AMERICA
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EUA
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UNITED STATES
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UNITED STATES OF AMERICA
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US
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USA